Compact city is an urban planning strategy aimed at promoting environmental, economic, and social sustainability through spatial configurations featured with relatively high density and mixed land use. The continuous growth in car ownership forces cities to construct more static transportation facilities such as parking lots, squeezing the activity spaces of residents and consequently giving rise to a series of efficiency and equity issues. Thus, the conflict between people and vehicles in compact cities is increasingly prominent and urgently needs to be addressed.
Time-division multiplexing (TDM), originally a term from the field of information and communication engineering, refers to the technique of transmitting multiple signals over the same communication channel in different time slots. In fact, the utilization of land resources for parking infrastructure in a TDM way has been a widespread spontaneous phenomenon to some extent. Thus, to provide references for the TDM planning and design of parking lots in compact cities, this study aims to address the following questions: How to identify urban spaces with TDM potential and determine potential demand? How to achieve it through detailed design of spaces? And, how to ensure effective implementation of the planning and design scheme with gamified public participation?
The TDM planning and design strategies for urban spaces need to comprehensively consider the usage demands of different groups at different time frames, requiring both technical expertise and practical logic. The conceptual framework proposed in this study, which was published on the journal of Landscape Architecture Frontiers and entitled "Research on Time-Division Multiplexing Planning and Design Strategies for Parking Lots under the Theory of Compact Cities", comprises three stages of supply and demand identification, planning and design, and community engagement. The key steps include identifying idle parking spaces and potential public activity needs, designing spaces tailored to specific activity needs, and increasing public acceptance through promotion. Firstly, in the stage of supply and demand identification, utilize spatiotemporal big data such as mobile signaling to characterize changes of the overall population flow in urban spaces. Secondly, in the planning and design stage, specific planning and design are carried out for potential parking lots based on the above results. In the last stage, TDM rules formed in the design proposal will be converted into interactive models, basing on site conditions. This forms a systematic planning strategy for the TDM design of parking lots.
This study focuses on a high-density built environment in the central urban area of a city in China. The region, characterized by its long-established development, dense buildings, and high population, is part of the old central urban area, covering approximately 2.65 km² and containing 50 surface public parking lots. This has resulted in a shortage of activity space for residents in the area and strained the relationship between pedestrians and vehicles.
Through planning methods, the parking lot can function as both a parking space and an activity space in appropriate times. For safety reasons, when parking demand is low and residents' activity demand is high, the parking space can be allocated to serve residents' activities. Conversely, when the parking demand is high, the activity space can be reduced or even eliminated. Finally, it is vital to ensure the implementation of the TDM strategies based on the spatial characteristics of the parking lot and with the assistance of corresponding guidance facilities.
However, this study also has some limitations. Firstly, due to differences in urban parking lot management entities and parking data, the determination of parking lot usage rates mainly relied on population flow data and manual field surveys, rather than the electronic technology at parking entrances directly, resulting in a relatively complex technical process. Due to limited conditions, this study failed to quantitatively evaluate the effectiveness of gamified community promotion and could only infer indirectly through the educational effect of public participation activities. Furthermore, the safety issues associated with coexisting activities and parking also require further in-depth research in spatial design, management, and operation.
